Carbureter



WILLIAM S. GUTHRIE, F TERRELL, TEXAS.

CARBURETER.

Specification of Letters Patent.

Patented Jan. 13, 1920.

Application led January 258; 1917. Serial No. 144,648.

To all whom fait may concern:

Be it known lhat l, Ullman S. (inquilini,

y a citizen of the United States, residinlgiz at eombustible mixture for internal combustion engines, and the primary object of the in '3. vention is to provide economical mixtures when the engine is running under normal `Conditions at the intermediate speeds.,

The invention relates particularly to a carhure-terV for controlling the quality of the eombustihle mixture llor internal combustion engines,y :for example those of antonmhlles Where the load is fre neatly varied,`suehen gines requiring a wid1 range of variation in the pro ortion of fuel. and air in order to efficient y and economically supply' the de mand made upon them.

" Pleasure automobiles are usually run at speeds ranging from l() to 35 miles per hour,

and a lean mixture is efficient at these speeds on reasonably good roads. This invention is `intended to provide the maximum mileage on fuel for automobiles when running at these intermediate speeds under normal conditions, such as when the roads are reasonably good and the load is comparatively light.

To accomplish the objert of this invention in a. type o1 rarhuretor as shown in the drawing, the disrharge end of an auxiliary air passage is I'sositioned in such manner that it opens; into the mixture passage at a point be youd the throttle when the latter is in a nearly closed position so it will supplY unearhureted air to the mixture passage at the inter-mediate engine speeds.

lith the above and other o'oierts in view.y the invention ronsists in the novel and useful provision, i'oru'latiolfi` constri'u'tion, eomhination, association and relative arrangrement of parts. shown in the drawing`r and finally pointed out in the claims.

The drawing` which is partly in section. shows a earhureter equipped with my inveniion and attached to the engine 1. the latter being eonventionallv shown and being somewhat reduced in size.

Referring to the drawing. the throttle valve 49 is positioned in the mixture passage and controls the flow of explosive mixture from the earbureter i5 to the engine in the usual way. The port .52 forms an auxiliary air passage that supplies air to the mixture passage at a point beyond the throttle when the latter is partially opened for the intermediate engine speeds.

lt is necessary lo malte the auxiliary air passage 5:2 less operative fortheslow engine speed in order that less air will How through the same at that time: and it is also desirable to avoid the use of any additional moving parte. The auxiliary air passage is, there fore, preferably positioned in the wall of the carburetor body adjacent the throttle sothat, when the latter is normally closed for the slow engine speed, it restricts the communication between the port 5.2 and the strong suction beyond the throttle and (when. a. thin throttle disk such as shown is used) opens the discharge end of said port into the mixture passage on the air intake side of the throttle. Te position of the auxiliary air passage with relation to the throttle may be varied somewhat from that shown in the drawing, as it may be desirable to have the auxiliary air passage so arranged that it will supply some air beyon.dthe throttle when the latter is normally closed or the slow engine speed., and an increased amount as the throttle is opened for the intermediate speeds.

It will he apparent that. the throttle, as it approaches the port 52 inelosing, serves as a shutter valve to vary the communication of the auxiliary air passage with the mixture passage beyond the throttle without the use of additional moving parts.\

The air pressure in the mixture passage on the air intake side of the throttle in this type of carhureter is practically atmospheric when the throttle is closed for slow engine speed. and very-little air, if any, will then flow through the auxiliary air passage into the mixture passage on the airintake side of the throttle. y

This control of the auxiliary air passage that is, by using a thin throttledisk, is preferably used in eouneetion with ('-arbuvreters having means for supplying hydrocarbon fuel to the mixture passage at a point beyond the throttle for the slow engine speeds, as by a fuel feed iet 51, so the Vent aetion ol the auxiliary air passage on the air intake side of the throttle will not interfere with the normal slow speed mixture.

The auxiliary air passage 552 may he Sullieiently large to insure the passage of ade quate air to provide the leanest possible mixture for the-intermediate speeds.

A manually actuated valve 55, which `is not necessary when the passage 52 is calibrated to correspond to the particular engine, may be provided to control the llow of air through-t e auxiliary air passage. This valve is provided with screw threads so that the turning of the @ame will open or close the auxiliary air passage as may be desired. This valve 55 ma be turned in to entirely close ofi' the auxiliary air supply to run the engine at times when a lean mixture is not eliicient, such as may be the case in cold weather before the engine is warmed up to a normal heat. The manually controlled valve makes it an easy matter to readily vary the quality of the explosive mixture at any time in t e operation of the engine. Various other forms of manually controlled valves may be employed to control the How of air through the auxiliary air passage.

When the throttle is fully opened for the maximum power of the engine, the auxiliary air passage 52 may continue to supply some air to the mixture passage, and it 1s prevented from impairing the power under these conditions by restricting the air inlet to the mixing chamber of the carbureter, as by restricting the Venturi passage 47 so it supplies no more additional air than required for developing the maximum power. In other Words, the difference in the suction in the venturi and at the port 52 at the high s eeds decreases the flow of auxiliary air through the passa e 53-52, because the venturi then deman s practically all the air then entering the air passage 46. The fuel nozzle 48 will supplyfuel for the maximum power f the engine in the usual way.

A by-pass passage 1s preferred to convey air to the auxiliary air passage 52 from the main air inlet passage 46 -of the carbureter, as by a`conduit 53. The point of connection of the by-passage 53 with the main air inlet assage is anterior to the fuel nozzle 48 and eyond the choke valve 54. The auxiliary air thus supplied to the auxiliary passage 52 will be non-hydrocarbon Huid, or uncarbureted air, because it does not pass by the fuel nozzle, and it will be of the same temperature as that supplied to the main air inlet passage. The auxiliary' air passage may obvious y be of any deslred shape in cross` section.

When internal combustion engines are equipped with economical carbureters they are usually hard to start, especially in cold weather, unless some means are employed to abnormally enrich the mixture when starting. In the present case a choke valve 54 is employed for this pur ose, but it will be understood that any ot er known enriching means may be employed.

With the choke valve 54l positioned anterior to the by-pass passage 53 as shown in the drawing, it will retard the How of air to the auxiliary air passage when closing the salue foi-,starting the engine, and this prevents the auxiliary air passage from admitting air to impair the starting of the engine.

A structure of the character shown and described is especially desirable for the reason that thc auxiliary air passage is controlled with but few moving parts, but the invention is intended to cover a Wide range of structures in addition to that shown in the drawing. I do not, therefore, Wish to be limited except as indicated by the subjoined claims.

I claimz- 1. A carburetcr comprising a body having a carbureting passage provided with an oscillating throttle valve, means for supplying fuel and air to said passage, an auxiliary air passage independent of the fuel su ply arranged so it discharges the greatest vo ume of air to the carbureting passage at a point beyond the air intake side of the throttle when the latter is partly closed and arranged so that the throttle valve in closing passes between the outlet of the auxiliary air passage and the engine.

2. A carbureter having a body with a mixing chamber therein, means for supplyin fuel to the mixing chamber, an air inta te passage, a venturi forming a restricted passage between the mixing chamber and the air intake passage, a throttle in tbe mixing chamber, an auxiliary air passage extended from said air inlet passage anterior to said venturi into the mixing chamber beyond the venturi, said auxiliary air passage being so arranged that. it by-passes the throttle when the latter is nearly closed, and also being so arranged that it normally supplies no carbureted air at any speed of the engine.

3. A carbureter comprising a body having a carbureting passage provided with an oscillating throttle valve, means for supplying fuel and air to said passage, an auxiliary air passage independent of the fuel supply arranged so it discharges the greatest volunie-of air to the carbureting passage at a point beyond the air intake side of the throttle when the latter is partly closed and arranged so that the throttle valve in' closing the air intake passage, a throttle in the mixing chamber, au auxiliary air passage extended from said air inlet passa e anterior to said venturi into the mixing c amber beyond the venturi, said auxiliary air passa re being so arranged that it by-passes tiie throttle when the latter is nearlyrclosed, and also being so arranged that it normally supplies no carbureted air at any speed of the engine, and an idling jet communicating with the source of fuel supply and discharging into the mixing chamber beyond the air intake side of the throttle.

5. A carburetor having a body with a mixing chamber therein, an air assage directing air to the mixing cham er, means for supplying fuel to the mixing chamber, an auxiliary air passage,communicating with the first named air passage and bypassing the throttle when the latter is nearly closed, said auxiliary air passage being so arranged that it normally supplies no carbureted air when idling the engine at the slowest speed,

and the throttle being so arranged that in closing it retards the suction on the auxiliary air passage.

6. A carbureter, a fuel feeding device, a throttle valve, an air passage directin air past said fuel feeding device, an auxi iary air passage communlcating aty two points with said first mentioned air passage and ily-passing said fuel feeding device and said throttle valve when the latter is partly open, said auxiliary air passage opening into the first named `air passage at a point adjacent the closed position of the throttle valve, the auxiliary air passage bein so arranged that it supplies no hydrocar on fuel at any speed of the engine.

In testimony whereof I have signed this specication in the presence of two subscribing witnesses.

WILLIAM S. GUTHRIE.

Witnesses:

C. T. MCCLUNG, C; H. VVIELAND.

Correction in Letters Patent No. 1,328,042

provement. in (rliurcbors,"

closing;

[SEAL] 1920, upon the applicationsl o William 4ing correction as follows: Page 1, lino 88, for the word "inclosing 4therein that the same may conform to the record of the caso in the It is hereby certified that in' Letters Patent. No. 1,328,042, granted January 13,

S. Guthrie, of Terrell, Texaspfor an irnizn error appears in the printed speccation requirread in und thun the said Letters Patent should bo read wigh this correction Patent. Oice.

Signed and sealed this 10th day o f February, A. D., 1920.

M. H. CULSTON,

Acting Commivis'ioner of Patents. 

